US Airways turned 76 years old on March 12 — and that will be the carrier's last birthday. The airline will operate its final flight later this year, ending a swift and safely paced merger with American Airlines.

American receives its SOC — or single operating certificate — a month ago, but the carriers haven't been fully integrated. While they are one on the technological side, the passengers still see them as two separate airlines. The next step is to align the reservations systems.

American Airlines Group plans to slowly kill off US Airways over a 90 day period, ensuring as smooth of a transition as possible. This is very different than the United-Continental merger or the US Airways-America West merger, both of which tried to merge the systems overnight. American did not give an exact date for the start or end of the process.

At the beginning of the 90 day period, American will announce a schedule change to become official at the end of the three months. After the announcement, all reservations for after the 90 days will have to be booked on AA.com. The last US Airways flight will operate at the end of those three months.

At the end of the 90 days, US Airways' reservations system, SHARES, will be shut down. The USAirways.com website will also disappear, likely becoming a redirect to AA.com.

The airline will have to retrain more than 10,000 people to SABRE, American's reservations system, from SHARES. There are more employees currently trained to use SABRE than SHARES.

The two carriers started codesharing soon after the merger became official. Flight numbers under the AA code are the same under the US code, making it simpler for the airline in the meantime.

However, the big jump isn't the last step in the journey to become a single airline. Labor issues still need to be resolved, and aircraft repainting into the new American Airlines livery is only expected to be completed by the end of 2017.